I think Diane's advice is very good. It is very possible, even likely that your whole marriage is on a downward spiral, but you can stop it, if willing.
Example, you said he claimed you weren't giving him sex, you didn't say if that was correct or not, but let's assume that, at least in his mind, it is correct. The normal response of the wife is to say something like, "Oh ishta, I feel so dirty, I don't want sex with you now." To which the normal response of the guy is, "There she goes again, I didn't get married to be celibate, and he turns back to the porn."
Both use the other as an excuse for their improper behavior and it damages and damages the relationship.
He already used you as an excuse for the porn. Are you also using him as an excuse for what you do?
Porn's message isn't very subtle, it is always available, it requires little or nothing from him, it wants him, it never judges him. A common response by wives to it is to turn into the guy's mother figure, and punish him, and withold sex from him, and so on. His wife becomes associated with punishment and strife, porn with fun and relaxation.
Much better to bring in a third party that can help you get back on track.
Marv